This invention relates to a structuring needle for working on felts, fiber batts, woven or knit fabric, also referred to collectively as a fiber web. By structuring needle there is meant a needle which works on a generally pre-compacted (pre-reinforced) material to lend it a desired structure.
Numerous types of structuring needles are in use in the manufacture of felts. The structuring needles are in most cases secured in a large number to a needle board of a structuring machine, and are caused to repeatedly pierce a pre-compacted material, such as a fiber batt, as the needle board executes swinging motions. This procedure results in a structuring of the fiber batt.
For such an operation frequently structuring needles are used, whose tip is provided with a groove-like recess. As a result of such a construction, individual filaments of the batt to be structured are captured by the recess at the tip of the structuring needle and pushed through the pre-compacted batt. Such a structuring needle is described in U.S. Pat. No. 3,792,512. The recess provided at the tip of the structuring needle (termed as a fork needle in that patent) is formed on either side by tines of more or less equal or different lengths.
U.S. Pat. No. 4,309,800 discloses a structuring needle (termed as a felting needle in that patent) provided with a recess at its working-part tip. The markedly flat recess has a groove-like structure of approximately triangular cross section.
U.S. Pat. No. 3,727,276 shows a structuring needle (termed as a felting needle in that patent), whose working-part tip is provided with a recess formed by a groove of rectangular cross section. The groove bottom is curved in the longitudinal direction of the groove.
As disclosed in German patent document No. DE-OS 2038478, the groove is extended into the working part of the structuring needle, so that it runs parallel to the working part beyond the working-part tip. Further, in the region of the working-part tip the groove has a wide opening, so that the groove flanks form an approximately right angle with one another. It is further disclosed in the German patent document to form at the working-part tip two mutually parallel-oriented notches which are separated from one another by a knife-like ridge. Such structuring needles have several tips, between which filaments may be received for pushing them into the material. Filaments, however, which extend transversely to the recesses may be severed by the central tip.
The different configurations of the shape of the working-part tip affect the properties of the structuring needle during its operation. It has been found, however, that the efficiency of the known structuring needles remains limited which means that a relatively high number of individual punctures is required until the desired structured felt is obtained from the pre-reinforced batt.